Chytré nanonástroje
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- ItemThe effect of synthesis procedure on hydrogen peroxidase-like catalytic activity of iron oxide magnetic particles(MDPI, 2020-09-27) Mukherjee, Atripan; Ashrafi, Amirmansoor; Švec, Pavel; Richtera, Lukáš; Přibyl, Jan; Brtnický, Martin; Kynický, Jindřich; Adam, VojtěchA comparative study was carried out using magnetic nanoparticles (MNPs) for the fabrication of non-enzymatic sensors for the continuous and rapid detection and monitoring of H2O2. Various MNPs, differing in terms of their synthesis procedure and modification, were synthesized and characterized by different techniques. The electrochemical catalytic activity of the synthesized MNPs toward the reduction in H2O2 was investigated by cyclic voltammetry. The naked MNPs showed the highest catalytic activity among all the synthesized MNPs. The biosensor based on the naked MNPs was then applied in the determination of H2O2 using chronoamperometry. The parameters such as the applied cathodic potential and the amount of MNPs on the developed biosensor were optimized. Moreover, the analytical figures of merit, including reproducibility (RSD = 6.14%), sensitivity (m = 0.0676 mu A mu M-1), limit of detection (LOD) = 27.02 mu mol L-1, and limit of quantification (LOQ) = 89.26 mu mol L-1 of the developed biosensor indicate satisfactory analysis. Finally, MNPs were successfully utilized for the determination of H2O2 in milk.
- ItemPreparation and Characterisation of Highly Stable Iron Oxide Nanoparticles for Magnetic Resonance Imaging(Hindawi Publishing Corporation, 2017-02-23) Kovář, David; Hubálek, Jaromír; Fohlerová, Zdenka; Malá, Aneta; Kalina, Michal; Jiřík, Radovan; Hlaváček, Antonín; Slabý, Ondřej; Skládal, Petr; Farka, Zdeněk; Mlčochová, Jitka; Starčuk jr., ZenonMagnetic nanoparticles produced using aqueous coprecipitation usually exhibit wide particle size distribution. Synthesis of small and uniform magnetic nanoparticles has been the subject of extensive research over recent years. Sufficiently small superparamagnetic iron oxide nanoparticles easily permeate tissues and may enhance the contrast in magnetic resonance imaging. Furthermore, their unique small size also allows them to migrate into cells and other body compartments. To better control their synthesis, a chemical coprecipitation protocol was carefully optimised regarding the influence of the injection rate of base and incubation times. The citrate-stabilised particles were produced with a narrow average size range below 2nm and excellent stability. The stability of nanoparticles was monitored by long-term measurement of zeta potentials and relaxivity. Biocompatibility was tested on the Caki-2 cells with good tolerance. The application of nanoparticles for magnetic resonance imaging (MRI) was then evaluated. The relaxivities and ratio calculated from MR images of prepared phantoms indicate the nanoparticles as a promising -contrast probe.
- ItemImproving cytocompatibility of CdTe quantum dots by Schiff-base-coordinated lanthanides surface doping(BioMed Central, 2018-04-19) Michálková, Hana; Strmiska, Vladislav; Škubalová, Zuzana; Dostálová, Simona; Michálek, Petr; Křížková, Soňa; Hynek, David; Kalina, Lukáš; Richtera, Lukáš; Moulick, Amitava; Adam, Vojtěch; Heger, ZbyněkBackground: Suitable fluorophores are the core of fluorescence imaging. Among the most exciting, yet controversial, labels are quantum dots (QDs) with their unique optical and chemical properties, but also considerable toxicity. This hinders QDs applicability in living systems. Surface chemistry has a profound impact on biological behavior of QDs. This study describes a two-step synthesis of QDs formed by CdTe core doped with Schiff base ligand for lanthanides [Ln (Yb3+, Tb3+ and Gd3+)] as novel cytocompatible fluorophores. Results: Microwave-assisted synthesis resulted in water-soluble nanocrystals with high colloidal and fluorescence stability with quantum yields of 40.9-58.0%. Despite induction of endocytosis and cytoplasm accumulation of Yb- and TbQDs, surface doping resulted in significant enhancement in cytocompatibility when compared to the un-doped CdTe QDs. Furthermore, only negligible antimigratory properties without triggering formation of reactive oxygen species were found, particularly for TbQDs. Ln-doped QDs did not cause observable hemolysis, adsorbed only a low degree of plasma proteins onto their surface and did not possess significant genotoxicity. To validate the applicability of Ln-doped QDs for in vitro visualization of receptor status of living cells, we performed a site-directed conjugation of antibodies towards immuno-labeling of clinically relevant target-human norepinephrine transporter (hNET), over-expressed in neuroendocrine tumors like neuroblastoma. Immuno-performance of modified TbQDs was successfully tested in distinct types of cells varying in hNET expression and also in neuroblastoma cells with hNET expression up-regulated by vorinostat. Conclusion: For the first time we show that Ln-doping of CdTe QDs can significantly alleviate their cytotoxic effects. The obtained results imply great potential of Ln-doped QDs as cytocompatible and stable fluorophores for various bio-labeling applications.
- ItemUV-Induced Nanoparticles-Formation, Properties and Their Potential Role in Origin of Life(MDPI, 2020-08-04) Nejdl, Lukáš; Zemánková, Kristýna; Havlíková, Martina; Burešová, Michaela; Hynek, David; Xhaxhiu, Kledi; Mravec, Filip; Matoušková, Martina; Adam, Vojtěch; Ferus, Martin; Kapuš, Jakub; Vaculovičová, MarkétaInorganic nanoparticles might have played a vital role in the transition from inorganic chemistry to self-sustaining living systems. Such transition may have been triggered or controlled by processes requiring not only versatile catalysts but also suitable reaction surfaces. Here, experimental results showing that multicolor quantum dots might have been able to participate as catalysts in several specific and nonspecific reactions, relevant to the prebiotic chemistry are demonstrated. A very fast and easy UV-induced formation of ZnCd quantum dots (QDs) with a quantum yield of up to 47% was shown to occur 5 min after UV exposure of the solution containing Zn(II) and Cd(II) in the presence of a thiol capping agent. In addition to QDs formation, xanthine activity was observed in the solution. The role of solar radiation to induce ZnCd QDs formation was replicated during a stratospheric balloon flight.
- ItemWater-dispersible TiO2 nanoparticles via a biphasic solvothermal reaction method(Springer, 2013-12-01) Mohan, Rajneesh; Drbohlavová, Jana; Hubálek, JaromírA biphasic solvothermal reaction method has been used for the synthesis of TiO2 nanoparticles (NPs). In this method, hydrolysis and nucleation occur at the interface of organic phase (titanium (IV) n-propoxide and stearic acid dissolved in toluene) and water phase (tert-butylamine dissolved in water) resulting in the nucleation of the stearic acid-capped TiO2 NPs. These NPs are hydrophilic due to hydrophobic stearic acid ligands and could be dispersed in toluene, but not in water. These stearic acid-capped TiO2 NPs were surface-modified with 2,3-dimercaptosuccinic acid (DMSA) in order to make them water soluble. The resultant TiO2 NPs were easily redispersed in water without any noticeable aggregation. The Rietveld profile fitting of X-ray diffraction (XRD) pattern of the TiO2 NPs revealed highly crystalline anatase structure. The average crystallite size of TiO2 NPs was calculated to be 6.89 nm, which agrees with TEM results. These results have important implications for the use of TiO2 in biomedical, environmental, and industrial applications.